Download Darwin and his Origin of Species

I.
HISTORICAL
PERSPECTIVE
II. DARWIN’S IDEA
III. THE EVIDENCE
Voyage of
the Beagle
(1831-1836)
12 shirts
1 carpet bag
1 pair slippers
1 pair of light walking shoes
1 microscope (a single lens model by Bancks & Son,
London)
1 geological compass
1 plain compass
2 pistols (with spare parts)
1 rifle (with spare parts)
1 telescope
1 pencil case
1 geological hammer
5 simisometers
3 mountain barometers
1 clinometer
1 camera obscura
1 hygrometer (belonged to FitzRoy)
1 taxidermy book
2-3 Spanish language books
14 other books, including Humboldt's "Personal
Narrative" and Lyell’s "Principles of Geology Vol.
1"
1 coin purse (Fanny Owen's gift)
1 pin with a lock of Sarah Owen's hair (Fanny's
sister)
Darwin’s Dilemma
1. 1836 – 1858 developed
theories on evolution
2. Reluctant to publish
3. In 1858, Alfred Russell
Wallace
 Similar theory
4. Darwin quickly finished
book
 Descent w/ Modification
 Adaptation by Natural
Selection
The Synthesis of Natural Selection
How organisms adapt to environment
Observation 1:
Variation w/in pop.
Observation 2:
Variation is heritable
Observation 3:
Not all survive and reproduce
• High reproductive effort
• Limited resources
• Unequal reproductive success
Observation 4:
Survival & Reproduction not Random
• Those with favorable traits leave more offspring
• Favorable traits accumulate in population
• Population is modified by NS
“Survival of the Fittest”
What’s the Evidence for natural selection?
Artificial Selection
•
•
Breed for desired traits
Large changes, short time
Maize
Teosinte
Fossil Record
•
•
Organisms in older rock look more dissimilar to present day
Newer rock strata should contain fossils that more closely
resemble current day organisms
Youngest
rocks
Oldest
rocks
Fossil Record
Oligocene
30MYA
45MYA
50MYA
55MYA
60MYA
Hyracotherium
(browsers)
55
Orohippus
Eocene
Hyracotherium
40MYA
Epihippus
35MYA
Mesohippus
(browsers)
40
Mesohippus
Anchitherium
(browsers)
20
Merychippus
(mixed feeders)
17
Neohipparion
(grazers)
14
Nannippus
(grazers)
12
Equus
(grazers)
5
Equus
Dinohippus
Onohippidion
Astrohippus
Pliohippus
Calippus
Protohippus
Cormohipparion
Nannippus
Merychippus
Parahippus
Desmatippus
25MYA
Miohippus
20MYA
Archaeohippus
15MYA
Kalobatippus
Miocene
Hypohippus
10MYA
Megahippus
5MYA
Hipparion
browsers
grazers
mixed feeders
Anchitherium
Pliocene
Neohipparion
Pleistocene
Pseudhipparion
Evolution of the Horse
Fossil Record
55 mya
browsers
40 mya
browsers
14 mya
grazers
20 mya
browsers
12 mya
grazers
17 mya
mixed feeder
5 mya
grazers
Fossil Record
Evolution of the whale
Millions of years ago
0
Modern whales
40
Basilosaurus
45
Dorudon
Rhodocetus
Ambulocetus
50
Pakicetus
Homology
Similar ancestry, different function
Mammalian forelimbs
Vestigial Structures
Leftover structures from evolutionary past
Pelvic bones – from when ancestors walked on land
Vestigial Structures
Leftover structures from evolutionary past
Human ‘tail’ – coccyx
Old cecum – appendix
Goose bumps - arrector pili muscle
Wisdom teeth – flatter face
Convergent Evolution
Similar traits evolve separately, but in similar environments
Same selectable pressures
Placental vs. marsupial mammals
Niche
Placental
Mammals
Burrower
Anteater
Mole
Nocturnal
Insectivore
Glider
Stalking
Predator
Wolf
Ocelot
Ring-tailed lemur
Numbat
Thylacine
Spotted cuscus
Marsupial mole
Marsupial
mouse
Chasing
Predator
Flying squirrel
Grasshopper
mouse
Lesser anteater
Australian
Marsupials
Climber
Flying phalanger
Tasmanian
quoll
Convergent Evolution
Asia & Australia
North America
Cactus
Euphorbia
DNA Sequence Comparison
How do these organisms relate to each other?
Cytochrome C Amino Acid Seq.
Evolutionary relationships based on DNA and protein
sequence – cytochrome C amino acid differences
0
1
10
11
13
17
28
Pseudogenes (dead genes)
Olfactory genes in mammals
Dog
Mouse
Rat
Human
Total # of
olf. genes
% dead
1,100
1,500
1,500
900
18%
20%
19.5%
63%
Functional
genes
902
1200
1207
333
Pseudogenes (dead genes)
Ascorbic acid (viatmin C) production
Primates, guinea pigs, and fruit bats only
mammals that can’t make vit C
•
•
•
Historical Perspective
Georges Cuvier  Catastrophism
Father of paleontology
Earth – 10,000 years old, catastrophic events
shaped it
Caused mass extinction, new species placed back
Historical Perspective
•
•
Charles Lyell  Uniformitarianism
Earth much older, slow gradual changes shaped it
Same processes still working today
Jean Baptiste Lamarck
Thomas Malthus
• Organisms change over • Populations outgrow food
time
• ‘Survival of fittest’
• Innate drive for perfection
• Inheritance of acquired
characteristics